Um if you good at math please help me and i will give you brainliest

Side a = 20.8                            

Side b = 20.5

Side c = 30

Side d = 2

Side e = 12.6

Step-by-step explanation:

We need to know what X is here is the equation:

3.2a+8+12.6++5(a+2)+(6a-3.5)=85.9

After doing the math you get a=4.

Apply this to each side and get the answer.

Side a = 20.8                            

Side b = 20.5

Side c = 30

Side d = 2

Side e = 12.6

Check

20.8+20.5+30+2+12.6=85.9

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12